Subtrochanteric femoral fractures are a subset of hip fractures generally treated with cephalomedullary nail fixation\[1\]. Single lag screw devices are most commonly-used, but integrated dual screw constructs have become increasingly popular\[2,3\]. The aim of this study was to compare outcomes of fixation of subtrochanteric femoral fractures using a single lag screw (Gamma3 nail, GN) with a dual screw device (InterTAN nail, IN). The primary outcome was mechanical failure, defined as lag screw cut-out, back-out, nail breakage or peri-implant fracture. Consecutive adult patients (18yrs) with subtrochanteric femoral fracture treated in a single centre were retrospectively identified using electronic records. Patients that underwent surgical fixation using either a long GN (2010–2017) or IN (2017–2022) were included. Medical records and radiographs were reviewed to identify complications of fixation. Cox regression analysis was used to determine the risk of mechanical failure and secondary outcomes by implant design. Multivariable regression models were used to identify predictors of mechanical failure. The study included 622 patients, 354 in the GN group (median age 82yrs, 72% female) and 268 in the IN group (median age 82yrs, 69% female). The risk of any mechanical failure was increased two-fold in the GN group (HR 2.44 \[95%CI 1.13 to 5.26\]; _p=0.024_). Mechanical failure comprising screw cut-out (_p=0.032_), back-out (_p=0.032_) and nail breakage (_p=0.26_) was only observed in the GN group. Technical predictors of failure included varus >5° for cut-out (OR 19.98 \[2.06 to 193.88\]; _p=0.01_), TAD;25mm for back-out (8.96 \[1.36 to 58.86\]; p=0.022) and shortening 1cm for peri-implant fracture (7.81 \[2.92 to 20.91\]; _p=<0.001_). Our results demonstrate that an intercalated screw construct is associated with a lower risk of mechanical failure compared with the a single lag screw device. Intercalated screw designs may reduce the risk of mechanical complications for patients with subtrochanteric femoral fractures

Summary Statement. We evaluated the mechanical strength of two cortical suspension devices by reproducing clinical situation for ACL reconstruction. A most important factor affecting the displacement during cyclic load was the length of the tendon rather than the length of the device. Introduction. A definite consensus for the optimal graft fixation technique to the femur in an anterior cruciate ligament (ACL) reconstruction has not been reached, although there have been several fixation techniques such as cortical suspension devices, transfixation devices, and interference screws. The purpose of this study was to evaluate the mechanical strength of two cortical suspension devices by reproducing actual clinical situation for ACL reconstruction in order to compare the TightRope. TM. as a new adjustable-length loop device and the EndoButton. TM. as a well-known fixed-length loop device under the consistent conditions. Methods. Two cortical suspension devices were tested under cyclic and pull-to-failure loading conditions in both an isolated device setup and a specimen setup to make a complete bone-device-tendon construct in porcine femurs and bovine flexor tendons using a tensile testing machine. Especially to examine the influence of the length of the tendon and the device, a total length of the bone tunnel was fixed to 35 mm, and an effective length of tendon in the bone tunnel was adjusted to 15 mm for the EndoButton group (EB), the TightRope 15 group (TR15) and 21 mm for the TightRope 21 group (TR21). Results. In the isolated device testing, the ultimate tensile strength of the EB (1430 ± 148 N) had significantly higher than that of the TR (866 ± 53 N), and also had significant difference in the specimen testing. The displacement in the isolated device testing after preloading for the EB (1.09 ± 0.29 mm) showed statistically lower than that for the TR (2.57 ± 1.19 mm), and had a significant difference after the cyclic load. In the specimen testing, on the other hand, the displacement after preloading showed no statistical difference between the EB (1.06 ± 0.30 mm), the TR21 (1.76 ± 2.28 mm) and the TR15 (1.51 ± 1.78 mm). But limiting only to the displacement from 1000 to 2000 cycles, the TR21 (0.92 ± 0.44 mm) showed statistically higher than the TR15 (0.49 ± 0.22 mm). Discussion. Although current results indicated that the EB had greater mechanical strength than the TR, both devices are presumed to provide sufficient fixation strength under clinical conditions. An important new finding from the current study was the measurement of initial displacement from the state of initial fixation until loading began and 50 N of tension was applied. In isolated device testing, the TR had significantly more displacement than the EB during pre-loading. This may reflect the TR's loops stretch until a certain amount of tension is applied. In the comparison of the TR21 and the TR15, the TR21 had a significantly larger displacement with a cyclic load from 1000 to 2000 cycles. This result indicated that a most important factor affecting the displacement during cyclic load was the length of the tendon rather than the length of the device. Thus, we should decide the length of the tendon in the bone tunnel to avoid the displacement of the graft

Osteoporosis is a progressive, chronic disease of bone metabolism, characterized by decreased bone mass and mineral density, predisposing individuals to an increased risk of fractures. The use of animal models, which is the gold standard for the screening of anti-osteoporosis drugs, raises numerous ethical concerns and is highly debated because the composition and structure of animal bones is very different from human bones. In addition, there is currently a poor translation of pre-clinical efficacy in animal models to human trials, meaning that there is a need for an alternative method of screening and evaluating new therapeutics for metabolic bone disorders, in vitro. The aim of this project is to develop a 3D Bone-On-A-Chip that summarizes the spatial orientation and mutual influences of the key cellular components of bone tissue, in a citrate and hydroxyapatite-enriched 3D matrix, acting as a 3D model of osteoporosis. To this purpose, a polydimethylsiloxane microfluidic device was developed by CAD modelling, stereolithography and replica molding. The device is composed by two layers: (i) a bottom layer for a 3D culture of osteocytes embedded in an osteomimetic collagen-enriched matrigel matrix with citrate-doped hydroxyapatite nanocrystals, and (ii) a upper layer for a 2D perfused co-culture of osteoblasts and osteoclasts seeded on a microporous PET membrane. Cell vitality was evaluated via live/dead assay. Bone deposition and bone resorption was analysed respectively with ALP, Alizarin RED and TRACP staining. Osteocytes dendrite expression was evaluated via immunofluorescence. Subsequently, the model was validated as drug screening platform inducing osteocytes apoptosis and administrating standard anti-osteoporotic drugs. This device has the potential to substitute or minimize animal models in pre-clinical studies of osteoporosis, contributing to pave the way for a more precise and punctual personalized treatment

Vacuum orthoses are being applied in the care of patients with foot and lower leg conditions, as ankle fractures or sprains. The lower leg is protected and immobilized, which increases mobility. Due to the design, the orthoses lead to a difference in leg length, i.e. the side with the orthosis becomes longer, which changes the gait kinematics. To prevent or mitigate the unfavourable effects of altered gait kinematics, leg length-evening devices (shoe lifts) are offered that are worn under the shoe on the healthy side. Our aim was to evaluate the effect of such a device on the normality of gait kinematics. Gait analysis was conducted with 63 adult, healthy volunteers having signed an informed consent form that were asked to walk on a treadmill at a speed of 4.5km/h in three different conditions:. barefoot - as reference for establishing the normality score baseline. with a vacuum orthosis (VACOPed, OPED GmbH, Germany) and a sport shoe. with a vacuum orthosis and a shoe lift (EVENup, OPED GmbH, Germany). Data was sampled using the gait analysis system MCU 200 (LaiTronic GmbH, Austria). The positions of the joint markers were exported from the software and evaluated for the joint angles during the gait cycle using custom software (implemented in DIAdem 2017, National Instruments). A normality score using a modification of the Gait Profile Score (GPS) was calculated in every 1%-interval of the gait cycle and evaluated with a Wilcoxon signed rank test. The GPS value was reduced by 0.33° (0.66°) (median and IQR) while wearing the shoe lift. The effect was statistically significant, and very large (W = 1535.00, p < .001; r (rank biserial) = 0.52, 95% CI [0.29, 0.70]). The significant reduction of the GPS value indicates a more normal gait kinematics while using the leg length-evening device on the contralateral shoe. This rather simple and inexpensive device thus might improve patient comfort and balance while using the vacuum orthoses

A biomechanical study assessing compressive failure load, strength and stiffness with three different interbody device shapes was performed in human cadaveric vertebrae. The custom-made interbody devices had similar cross-sectional areas and specimens were tested with 20% or 40% coverage of indentor to endplate area. Axial compressive load was applied at 0.2mm/s to a depth equivalent to 20% of the vertebral height. The clover-leaf shaped device resulted in significantly higher failure load, strength and stiffness over the elliptical and the kidney shaped devices for both areas of coverage. The clover-leaf shaped devices extended over stronger periphery regions of the endplates and resulted in stronger interface properties. To determine if two novel interbody cage shapes, the kidney and the clover-leaf, are biomechanically superior to a standard elliptical shape of similar cross sectional area. Uniaxial compression tests with unrestricted rotations were carried out on the superior endplates of forty-eight thoracolumbar (T9-L2) vertebrae with one of three shaped indentors covering 20% or 40% of the endplate area. Compressive load was applied using a servohydraulic testing machine at 0.2mm/s, to depth equivalent to 20% of the vertebral height. Failure load, strength and stiffness were compared. The clover-leaf shaped indentors resulted in higher failure load (53% average increase), higher strength (67% average increase) and higher construct stiffness (43% average increase), and these results were significant (p< 0.05). Larger indentor coverage area of 40% also resulted in significantly higher failure loads over 20% coverage (75% average increase). Current elliptical interbody devices are placed over the central region of the endplate, which is also the weakest. A clover-leaf shaped device extended over the stronger peripheral regions of the endplates and resulted in improved bone-implant interface properties. This implant if implemented in vivo could potentially reduce implant subsidence and lead to better long-term outcomes in osteoporotic patients. The novel clover-leaf shaped indentor displayed superior bone-implant interface properties. Larger interbody devices should be used when possible to improve interface properties. Implant subsidence in osteoporotic patients could be significantly reduced with a clover-leaf shaped device, leading to better long-term outcomes. Funding: Funding from the Canadian Institutes for Health Research

Freehand distal interlocking of intramedullary nails is technical demanding and prone to handling issues. It requires the surgeon to precisely place a screw through the nail under x-ray. If not performed accurately it can be a time consuming and radiation expensive procedure. The aims of this study were to assess construct and face validity of a new training device for distal interlocking of intramedullary nails. 53 participants (29 novices and 24 experts) were included. Construct validity was evaluated by comparing simulator metrics (number of x-rays, nail hole roundness, drill tip position and accuracy of the drilled hole) between experts and novices. Face validity was evaluated by means of a questionnaire concerning training potential and quality of simulated reality using a 7-point Likert scale (range 1-7). Mean realism of the training device was rated 6.3 (range 4-7) and mean training potential as well as need for distal interlocking training was rated 6.5 (range 5-7) with no significant differences between experts and novices, p≥0.236. All participants stated that the simulator is useful for procedural training of distal nail interlocking, 96% would like to have it at their institution and 98% would recommend it to their colleagues. Total number of x-rays were significantly higher for novices (20.9±6.4 vs. 15.5±5.3), p=0.003. Successful task completion (hit the virtual nail hole with the drill) was significantly higher in experts (p=0.04; novices hit: n=12; 44,4%; experts hit: n=19; 83%). The evaluated training device for distal interlocking of intramedullary nails yielded high scores in terms of training capability and realism. Furthermore, construct validity was established as it reliably discriminates between experts and novices. Participants see a high further training potential as the system may be easily adapted to other surgical task requiring screw or pin position with the help of x-rays

Acute Compartment Syndrome (ACS) is an orthopaedic emergency that can develop after a wide array of etiologies. In this pilot study the MY01 device was used to assess its ease of use and its ability to continuously reflect the intracompartmental pressure (ICP) and transmit this data to a mobile device in real time. This preliminary data is from the lead site which is presently expanding data collection to five other sites as part of a multi-center study. Patients with long bone trauma of the lower or upper extremity posing a possibility of developing compartment syndrome were enrolled in the study. Informed consent was obtained from the patients. A Health Canada licensed continuous compartmental pressure monitor (MY01) was used to measure ICP. The device was inserted in the compartment that was deemed most likely to develop ACS and ICP was continuously measured for up to 18 hours. Fractures were classified according to the AO/OTA classification. Patient clinical signs and pain levels were recorded by healthcare staff during routine in-patient monitoring and were compared to the ICP from the device. Important treatment information was pulled from the patient's chart to help correlate all of the patient's data and symptoms. The study period was conducted from November 2020 through December 2021. Twenty-six patients were enrolled. There were 17 males, and nine females. The mean age was 38 years (range, 17–76). Seventeen patients received the device post-operatively and nine received it pre-operatively. Preliminary results show that post-operative ICPs tend to be significantly higher than pre-operative ICPs but tend to trend downwards very quickly. The trend in this measurement appears to be more significant than absolute numbers which is a real change from the previous literature. One patient pre-operatively illustrated a steep trend upwards with minimal clinical symptoms but required compartment release at the time of surgery that exhibited no muscle necrosis. The trend in this patient was very steep and, as predicted, predated the clinical findings of compartment syndrome. This trend allows an early warning signal of the absolute pressure, to come, in the compartment that is being assessed by the device. Preliminary results suggest that this device is reliable and relatively easy to use within our institutions. In addition it suggests that intracompartmental pressures can be higher immediately post-op but lower rapidly when the patient does not develop ACS. These results are in line with current literature of the difference between pre and post-operative baselines and thresholds of ICP, but are much more striking, as continuous measurements have not been part of the data set in most of past studies. Further elucidation of the pressure thresholds and profiles are currently being studied in the ongoing larger multicenter study and will add to our understanding of the critical values. This data, plus the added value of continuous trends in the pressure, upwards or downwards, will aid in preventing muscle necrosis during our management of these difficult long bone fractures

Lumbar fusion remains the gold standard for the treatment of discogenic back pain. Total disc replacement has fallen out of favor in many institutions. Other motion preservation alternatives, such as nucleus replacement, have had limited success and none are commercially available at this time. Two prospective, nonrandomized multicenter studies of lumbar disc nucleus replacement using the PerQdisc 2.0 nucleus replacement device in patients with lumbar discogenic back pain. Early clinical results are presented. A total of 16 patients from 4 international sites (Germany, Paraguay, Canada and Belgium) were enrolled in the trial between May 2019 and February 2021. Data collection points include baseline and postoperatively at 1, 2, 6, and 12 months. Clinical outcome measures were obtained from the Visual Analog Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), SF-12V2, Analgesic Score (AS), and radiographic assessments. Prospectively gathered data on patient reported outcomes, neurological outcome, surgical results, radiological analysis, and any adverse events. 16 patients had successful implantation of the device. There have been no expulsions of the device. Early postoperative results are available in 13/16 patients at 6 months and 11/16 patients at 12 months. There have been 4 (25%) revision surgeries 3–12 months post implantation between the two trials. 12 of 13 (92%) patients had Minimal Clinically Important Difference (MCID) in ODI at 6 months and 10 of 11 (91%) at 12 months. Mean decrease in ODI from baseline to 12 months was 44.8. At 12 months 8 (73%) patients are not taking pain medication, 1 (9%) patient is taking a narcotic for pain management. 73% of patients are working without restrictions at 12 months post implant. Early clinical and technical results are encouraging. Long term follow up is essential and is forthcoming. Additional patient recruitment and data points are ongoing. FDA/Drug Status Investigational/Not approved

Abstract. Introduction. Cryocompression therapy after knee surgery is widely utilised for post-operative rehabilitation. Skin temperature should be reduced to 10–15°C to maximise the therapeutic benefits while avoiding risks of adverse events. Some cryocompression devices offer control over the temperature of the ice-water circulated through a cuff. The degree to which this corresponds to the achieved skin temperature during a treatment is unknown. Methods. 30 healthy participants volunteered for this prospective randomised crossover trial involving the use of a cryocompression device. Each underwent a 30-minute test in all of five conditions: A, B, C, D and Control. Conditions corresponded to device temperature settings of 6, 8, 10, 12°C and no ice-water circulation, respectively. Skin temperature was measured prior to the cuff being applied, then every 5 minutes during a test. Results. Groups A, B, C and D significantly reduced skin temperature relative to the Control condition (p<0.05). Mean baseline skin temperatures did not significantly differ between groups. Mean skin temperatures after 30 minutes were 13.2 ± 1.9°C (Group A), 14.4 ± 1.5°C (Group B), 16.3 ± 1.8°C (Group C), 18.3 ± 1.7°C (Group D), and 30.8 ± 2.3°C (Control). Conclusions. The cryocompression device successfully reduced the skin temperature to within the therapeutic range. However, temperature settings did not correspond to skin temperatures achieved. To optimise the therapeutic benefit of treatment with this device, the 6°C setting is recommended. (Note: these are preliminary results from on an ongoing study, comprising 72% of the final dataset. Full results will be presented at BASK 2022)

Abstract. MAGnetic Expansion Control (MAGEC) rods are used in the surgical treatment of children with early onset scoliosis. The magnetically controlled lengthening mechanism enables rod distractions without the need for repeated invasive surgery. The CE certification of these devices was suspended in March 2021 due, primarily, to performance evidence gaps in the documents provided by the manufacturer to regulators and notified bodies. MAGEC rods are therefore not permitted for use in countries requiring CE marking. This was a survey of 18 MAGEC rod surgeons in the UK about their perception of the impact of the CE suspension on the clinical management of their patients. Unsurprisingly, virtually all perceived a negative impact, reflecting the complexity of this patient group. Reassuringly, these surgeons are highly experienced in alternative treatment methods. Cite this article: Bone Jt Open 2022;3(2):155–157

An increasing elderly population means joint replacement surgery numbers are projected to increase, with associated complications such as periprosthetic joint infections (PJI) also rising. PJI are particularly challenging due to antimicrobial resistant biofilm development on implant surfaces and surrounding tissues, with treatment typically involving invasive surgeries and systemic antibiotic delivery. Consequently, functionalisation of implant surfaces to prevent biofilm formation is a major research focus. This study characterises clinically relevant antimicrobials including gentamicin, clindamycin, daptomycin, vancomycin and caspofungin within a silica-based, biodegradable sol-gel coating for prosthetic devices. Antimicrobial activity of the coatings against clinically relevant microorganisms was assessed via disc diffusion assays, broth microdilution culture methods and the MBEC assay used to determine anti-biofilm activity. Human and bovine cells were cultured in presence of antimicrobial sol-gel to determine cytotoxicity using Alamar blue and antibiotic release was measured by LC-MS. Biodegradability in physiological conditions was assayed by FT-IR, ICP-MS and measuring mass change. Effect of degradation products on osteogenesis were studied by culturing mesenchymal stem cells in the presence of media in which sol-gel samples had been immersed. Antimicrobial-loaded coatings showed strong activity against a wide range of clinically relevant bacterial and fungal pathogens with no loss of activity from antibiotic alone. The sol-gel coating demonstrated controlled release of antimicrobials and initial sol-gel coatings showed no loss of viability on MSCs with gentamicin containing coatings. Current work is underway investigating cytotoxicity of sol-gel compositions against MG-63 cells and primary osteoblasts. This research forms part of an extended study into a promising antimicrobial delivery strategy to prevent PJI. The implant coating has potential to advance PJI infection prevention, reducing future burden upon healthcare costs and patient wellbeing

Malalignment is a common complication following tibial surgery, occurring in 10% of fractures. This is associated with prolonged healing time and non-union. It occurs due to inability to maintain a satisfactory reduction. A reduction device, such as the Staffordshire Orthopaedic Reduction Machine (STORM), permits the surgeon to manipulate the fracture and hold it reduced. A retrospective parallel case series was undertaken of all patients undergoing tibial nails over a six-year period from 2014 to 2021. Patient demographics were obtained from medical records. Operative times obtained from the theatre IT system and included the time patient entered theatre and surgical start and finish times for each case. Anteroposterior and lateral long leg post-operative radiographs were reviewed. Angulation was measured in both coronal and sagittal planes, by two separate orthopaedic surgeons. A reduction was classified to be ‘mal-aligned’ if the angle measured was greater than 5 degrees. One tailed unpaired t-test was used to compare alignment in each plane. Bony union was assessed on subsequent radiographs and was determined according to the Radiographic Union Score for Tibial Fractures. 31 patients underwent tibial nail during the time period. 8 patients were lost to follow up and were excluded. Of the remaining 23 patients, the STORM device was utilised in 11. The overall mean alignment was acceptable across all groups at 2.17° in the coronal plane and 2.56° in the saggital plane. Analysing each group individually demonstrated an improved alignment when STORM was utilised: 1.7° (1°–3°) vs 2.54° (0°–5°) for the coronal plane and 1.6° (0°–3°) vs 3.31° (0°–9°) in the saggital plane. This difference was significant in saggital alignment (p=0.03) and showed a positive trend in coronal alignment, although was not significant (p=0.08). The time in theatre was shorter in the control group with a mean of 113 minutes (65 to 219) in comparison to STORM with a mean of 140 minutes (105 to 180), an increased theatre time of 27 minutes (p=0.04). This study demonstrates that STORM can be used in the surgical treatment of tibial fractures resulting in improved fracture alignment with a modest increase in theatre time

Introduction. Total Knee Arthroplasty (TKA) has been demonstrated to drastically improve a patient's quality of life. The outcomes following TKA are often reported by subjective patient reported outcome measurements (PROMs). However, there are few objective outcome measures following TKA, limiting the amount of information physicians can use to effectively guide a patient's recovery, especially in the first 3 weeks. Newly developed knee sensors have been able to ameliorate this problem by providing the physician with previously unobtainable objective data. Our study aims to evaluate the use of a wearable knee sensor device to measure functional outcomes (range of motion and steps) in real time. Methods. 29 patients who underwent primary, unilateral TKA were recruited for this IRB approved study. Patients were instructed how to use the device and associated mobile phone application preoperatively (Figure 1) and provided knee sensors to wear postoperatively (Figure 2). Patients wore the device for 3 weeks postoperatively to allow for data collection. The device recorded range of motion, number of steps, and percentage of physical therapy exercises completed. Patients were grouped by gender, age (<69 or >=70 years old), and BMI (<30 and >=30 kg/m2) for analysis of functional outcome measurements (maximum flexion, minimum extension, and number of steps). Unpaired two-sample t-tests were used to analyze differences between the groups. Results. Patients were able to tolerate wearing the device without complication and the device collected functional outcome data appropriately as designed. After brief instruction, both patients and physicians were able to monitor patient data via the mobile phone application in real time. The mean maximum flexion and minimum extension did not significantly change from postoperative week 1 to postoperative week 2 and week 3. However, the mean number of steps taken increased from 4,923 steps in postoperative week 1 to 8,163 steps week 2 (p=0.01) and 11,615 steps week 3 (p<0.001) postoperatively. There were no statistically significant differences in maximum flexion, minimum extension, and number of steps between the different gender, age, and BMI groups. Discussion and Conclusion. The knee sensor device used in our study proved to be useful in providing objective functional outcomes following TKA. The device was well tolerated by patients and the mobile phone applications were easy to use for the physicians and the patients. Real time tracking of patients' own range of motion, number of steps, and percentage of exercises completed may motivate them to further their own recovery process. There were wide ranges in the number of steps taken during each postoperative time interval. These results may help identify individuals who are recovering at a faster rate or those who may need more focused physical therapy. Subsequent larger studies can utilize the device to elucidate previously unknown recovery trends among different groups of patients following TKA. In the future, the device's ability to collect real time functional outcome data will allow physicians and other healthcare providers to create individualized physical therapy plans, thereby optimizing the patient's recovery process. For figures, tables, or references, please contact authors directly

Rotational laxity increases the risk of anterior cruciate ligament (ACL) injuries and residual rotational laxity can result in inferior surgical outcomes and risk of retears. The dynamic rotatory knee stability can be assessed through manual examination, but it is limited to the surgeon's experience and it provides inaccurate measurements, highlighting the need for objective measurement of knee rotational laxity. The objective measurement of knee laxity can help to better identify patients that may benefit from conservative treatment or those that require surgical treatment with or without concomitant extra-articular procedures. We rely in Porto Knee Testing Device (PKTD®) to accurately measure sagittal and rotatory laxity of the knee, either individually or in a combined fashion. The PKTD® is safe and can be used in combination with CT or MRI, which allows to assess both the “anatomy” and the “function” in the same examination. By this way, we may have a total ACL rupture and a stable knee not requiring surgery or, on the other hand, the same injury scenario but with an unstable knee that requires surgical intervention (with or without lateral extra-articular tenodesis). In cases of partial ACL tears, it may be possible to identify some ligamentous fibers that remain functional, where the conservative treatment or augmentation techniques can provide satisfactory results. It can also identify when a posteromedial or posterolateral instability is associated. The PKTD® can also be used to follow-up the laxity results of conservative and surgical procedures and contribute to the decision-making of return to sports

This study compares outcomes of fixation of subtrochanteric femoral fractures using a single lag screw (Gamma3 nail, GN) with a dual lag screw device (InterTAN nail, IN). The primary outcome was mechanical failure, defined as lag screw cut-out, back-out, nail breakage or peri-implant fracture. Technical factors associated with mechanical failure were also identified. All adult patients (>18yrs) with a subtrochanteric femoral fracture treated in a single centre were retrospectively identified using electronic records. Included patients underwent surgical fixation using either a long GN (2010–2017) or IN (2017–2022). Cox regression analysis was used to determine the risk of mechanical failure and technical predictors of failure. The study included 587 patients, 336 in the GN group (median age 82yrs, 73% female) and 251 in the IN group (median age 82yrs, 71% female). The IN group exhibited a higher prevalence of osteoporosis (p=0.002) and CKD□3 (p=0.007). There were no other baseline differences between groups. The risk of any mechanical failure was increased two-fold in the GN group (HR 2.51, p=0.020). Mechanical failure comprising screw cut-out (p=0.040), back-out (p=0.040) and nail breakage (p=0.51) was only observed in the GN group. The risk of peri-implant fracture was similar between the groups (HR 1.10, p=0.84). Technical predictors of mechanical included varus >5° for cut-out (HR 15.61, p=0.016), TAD>25mm for back-out (HR 9.41, p=0.020) and shortening >1cm for peri-implant fracture (HR 6.50, p=<0.001). Dual lag screw designs may reduce the risk of mechanical complications for patients with subtrochanteric femoral fractures

Aims. This study aims to enhance understanding of clinical and radiological consequences and involved mechanisms that led to corrosion of the Precice Stryde (Stryde) intramedullary lengthening nail in the post market surveillance era of the device. Between 2018 and 2021 more than 2,000 Stryde nails have been implanted worldwide. However, the outcome of treatment with the Stryde system is insufficiently reported. Methods. This is a retrospective single-centre study analyzing outcome of 57 consecutive lengthening procedures performed with the Stryde nail at the authors’ institution from February 2019 until November 2020. Macro- and microscopic metallographic analysis of four retrieved nails was conducted. To investigate observed corrosion at telescoping junction, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) were performed. Results. Adjacent to the nail’s telescoping junction, osteolytic changes were observed in bi-planar radiographs of 20/57 segments (35%) after a mean of 9.5 months (95% confidence interval 7.2 to 11.9) after surgery. A total of 8/20 patients with osseous alterations (40%) reported rest and ambulation pain of the lengthened segment during consolidation. So far, 24 Stryde nails were retrieved and in 20 (83%) macroscopic corrosion was observed at the nail’s telescoping junction. Before implant removal 11/20 radiographs (55%) of lengthened segments with these 20 nails revealed osteolysis. Implant retrieval analysis by means of SEM showed pitting and crevice corrosion. EDX detected chromium as the main metallic element of corrosion. Conclusion. Patients are exposed to the risk of implant-related osteolysis of unclear short- and long-term clinical consequences. The authors advocate in favour of an early implant removal after osseous consolidation. Cite this article: Bone Joint Res 2021;10(7):425–436

Stand-alone anterior lumbar interbody fusion (ALIF) provides the opportunity to avoid supplemental posterior fixation. This may reduce morbidity and complication rate, which is of special interest in patients with reduced bone mineral density (BMD). This study aims to assess immediate biomechanical stability and radiographic outcome of a stand-alone ALIF device with integrated screws in specimens of low BMD. Eight human cadaveric spines (L4-sacrum) were instrumented with SynFix-LR™ (DePuy Synthes) at L5/S1. Quantitative computed tomography was used to measure BMD of L5 in AMIRA. Threshold values proposed by the American Society of Radiology 80 and 120 mg CaHa/mL were used to differentiate between Osteoporosis, Osteopenia, and normal BMD. Segmental lordosis, anterior and posterior disc height were analysed on pre- and postoperative radiographs (Fig 1). Specimens were tested intact and following instrumentation using a flexibility protocol consisting of three loading cycles to ±7.5 Nm in flexion-extension, lateral bending, and axial rotation. The ranges of motion (ROM) of the index level were assessed using an optoelectronic system. BMD ranged 58–181mg CaHA/mL. Comparison of pre- and postoperative radiographs revealed significant increase of L5/S1 segmental lordosis (mean 14.6°, SD 5.1, p < 0.001) and anterior disc height (mean 5.8mm, SD 1.8, p < 0.001), but not posterior disc height. ROM of 6 specimens was reduced compared to the intact state. Two specimens showed destructive failure in extension. Mean decrease was most distinct in axial rotation up to 83% followed by flexion-extension. ALIF device with integrated screws at L5/S1 significantly increases segmental lordosis and anterior disc height without correlation to BMD. Primary stability in the immediate postoperative situation is mostly warranted in axial rotation. The risk of failure might be increased in extension for some patients with reduced lumbar BMD, therefore additional posterior stabilization could be considered. For any figures or tables, please contact the authors directly

Objectives. Bioresorbable orthopaedic devices with calcium phosphate (CaP) fillers are commercially available on the assumption that increased calcium (Ca) locally drives new bone formation, but the clinical benefits are unknown. Electron beam (EB) irradiation of polymer devices has been shown to enhance the release of Ca. The aims of this study were to: 1) establish the biological safety of EB surface-modified bioresorbable devices; 2) test the release kinetics of CaP from a polymer device; and 3) establish any subsequent beneficial effects on bone repair in vivo. Methods. ActivaScrew Interference (Bioretec Ltd, Tampere, Finland) and poly(L-lactide-co-glycolide) (PLGA) orthopaedic screws containing 10 wt% β-tricalcium phosphate (β-TCP) underwent EB treatment. In vitro degradation over 36 weeks was investigated by recording mass loss, pH change, and Ca release. Implant performance was investigated in vivo over 36 weeks using a lapine femoral condyle model. Bone growth and osteoclast activity were assessed by histology and enzyme histochemistry. Results. Calcium release doubled in the EB-treated group before returning to a level seen in untreated samples at 28 weeks. Extensive bone growth was observed around the perimeter of all implant types, along with limited osteoclastic activity. No statistically significant differences between comparative groups was identified. Conclusion. The higher than normal dose of EB used for surface modification did not adversely affect tissue response around implants in vivo. Surprisingly, incorporation of β-TCP and the subsequent accelerated release of Ca had no significant effect on in vivo implant performance, calling into question the clinical evidence base for these commercially available devices. Cite this article: I. Palmer, S. A. Clarke, F. J Buchanan. Enhanced release of calcium phosphate additives from bioresorbable orthopaedic devices using irradiation technology is non-beneficial in a rabbit model: An animal study. Bone Joint Res 2019;8:266–274. DOI: 10.1302/2046-3758.86.BJR-2018-0224.R2

Introduction. Acetabular reconstruction of a total hip arthroplasty (THA) for a case with severe bone loss is most challenging for surgeon. Relatively high rate of failure after the reconstruction surgery have been reported. We have used Kerboull-type acetabular reinforcement devices with morsellised or bulk bone allografts for these cases. The purpose of this study was to examine the midterm results of revision THA using Kerboull-type acetabular reinforcement devices. Patients and methods. We retrospectively reviewed 20 hips of revision THA (20 patients) between February 2002 and August 2010. The mean age of the patients at the time of surgery was 67.4 years (range 45–78). All of the cases were female. The mean duration of follow-up was 6.5 years (range 2.1–10.4). The reasons of revision surgeries were aseptic loosening in 10 hips, migration of bipolar hemiarthroplasty in 8 hips, and rheumatoid arthritis in 2 hips. We classified acetabular bone defects according to the American Academy of Orthopaedic Surgeons (AAOS) classification; we found two cases of Type II and eighteen cases of Type III. In terms of bone graft, we performed both bulk and morsellised bone grafts in 6 hips and morsellised bone grafts only in 14 hips. We assessed cup alignment using postoperative computed tomography (CT) and The post-operative and final follow-up radiographs were compared to assess migration of the implant. We measured the following three parameters: the angle of inclination of the acetabular device (Fig. 1); the horizontal migration (Fig. 2a); and vertical migration (Fig. 2b). Substantial migration was defined as a change in the angle of inclination of more than 3 degrees or migration of more than 3 mm. The pre- and postoperative hip functions were evaluated using the Japanese Orthopaedic Association (JOA) hip score. Results. The mean cup inclination and anteversion were 38.4 degrees and 10.6 degrees, respectively. The mean change in the angle was 1.9 degrees in inclination of the device. The average horizontal migration was 1.0 mm, and the vertical migration was 2.0 mm. Only one hip showed substantial migration with breakage of the device. This failure case represented a large amount of posterior pelvic tilt in standing position postoperatively. The mean JOA hip score was increased from 46.7 to 74.8. Discussion. Poor outcome using Kerboull-type reinforcement plate with morsellised bone graft only has been demonstrated by many reports. In these literatures, bulk bone graft was recommended particularly in the case of large bone defect such as larger than half of the rounded plate of the device or more than 2 cm of thickness. In our case series, acetabular reconstruction using a Kerboull- type acetabular reinforcement device and bone graft gives satisfactory mid-term results even with morsellized bone graft only. One possible interpretation is that most of our cases had relatively small bone defect according to the staging of severity of the superior segmental bone loss made by Kawanabe et al. We suggest that the progressive posterior pelvic tilt should be considered to be a risk of poor outcome of the acetabular reconstruction using this device. To view tables/figures, please contact authors directly

Introduction. Functional stability is a new concept stating that lower tensions than expected are enough to achieve joint stability leading to proper function after TKA. To check this rationale clinically, a new electronic device (DLB bicon sensorplate) was used intraoperatively to measure ligament tension and allow the surgeon to proper balance the knee after TKA insertion. In this study a controlled clinical analysis at 1 YR follow-up is reported. Methods. A cohort of 25 patients was treated in a single centre, single surgeon study to quantify the influence of the use of this electronic device in the short- and midterm results (DLB Group). A control cohort of 25 patients were treated without the device (Control Group). All patients were monitored by the use of OKS, AKSS and FJS; beside that, the muscle function before and after the surgery was tested and a load distribution analysis was performed. The FU examinations were done after 6 weeks, 3 months, 6 months and 1 yr. All the patients finished the study and could be included. Results. DLB group showed an improvement of 10% in the OKS compared to the Control Group, even if the preoperative measurements were lower (OKS DLB Group improve from 18 to 44, Control group from 26 to 40). Also the AKSS shows an improvement around 10% in the DLB Group (38 to 97) compared to the Control Group (53 to 93); the knee score improved also in the same matter (DLB Group 32 to 91, Control Group 40 to 91). Similar improvement in the FJS was also found in the DLB Group and in the Control Group. The muscles function testing showed a faster recovery of the muscle status and restore of the original functionality in the DLB Group. DLB Group patients recovered approx. 1/3 of the time faster than Control Group ones. The load distribution analysis shows a better load distribution with a more normal gait in the DLB Group. Summary. In all PROMs the group treated by the support of the device showed a significant improvement and better clinical outcome, also the subjective patient satisfaction was higher in the DLB Group, where the proper ligament tension (aimed to functional stability) was achieved. Conclusion. The use of sensory devices to secure proper balancing is justified by several studies. This study proves the efficacy of using a sensory device intraoperatively to measure the necessary ligament tension to achieve functional stability in a controlled single centre study